Abstract

Microstructural features and magnetocaloric properties of Ni52Mn26Ga22 melt-spun ribbons were studied. Results show that there are four types of differently oriented variants of seven-layered modulated (7M) martensite at room temperature, being twin-related one another and clustered in colonies. Due to the coupled magnetic and structural transformations between parent austenite and 7M martensite, the melt-spun ribbons exhibit a significant magnetocaloric effect. At an applied magnetic field of 5 T, an absolute maximum value of the isothermal magnetic entropy change of 11.4 J kg−1 K−1 is achieved with negligible hysteresis losses.

Received 20 January 2012Accepted 03 April 2012Published online 27 April 2012

Acknowledgments:

This work is supported by the National Natural Science Foundation of China (Grant No. 50820135101), the Ministry of Education of China (Grant Nos. 2007B35, 707017, and IRT0713), the Fundamental Research Funds for the Central Universities of China (Grant Nos. N090602002 and N100702001), the French-Chinese International ANR Project OPTIMAG (No. ANR-09-BLAN-0382), and the Sino-French Cai Yuanpei Program (No. 24013QG). J.L.S.L. acknowledges the support received from Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología (LINAN, IPICyT), and CONACYT, Mexico (Grant Nos. CB-2010-01-156932 and CB-2010-01-157541). C.F.S.V. thanks CSIC, Spain, for the Ph.D. Grant received (JAEPRE-08-00508).